Rotary spark gap



June 10, 1952 R. s. STANTON 2,599,951

, ROTARY SPARK GAP Filed Oct. 9, 1945 I'll/1,

- T (ml FIG.3 'F'l.4

INVENTOR RUSSELL S. STANTON ATTORNEY Patented June 10, 1952 mesneassignments, to the United States of Americans represented bytheSecretary of the Application'flctober 9, 19.45,"Serial"'No. 621,338

l'lClaims. (CL-.31'3-l491) i "This invention relates to a rotary sparkgap generator and :more particularly "to such :a genorator adapted toprovide *uniform spark gen-- *eration and 1ong=electrode lifeunderconditions Rotary-spark gap generators heretofore known in the artand used as modulator switches Ior throwing an electrical pulse upon amagnetron :are usually so designed that the faces of the sparkingelectrodes are parallel at the instant sparking zoccurs. iSuch:gen'erators have proven to :be impractical tor the handling of largecurrents of the :order of one thousand :amperes at usual duty cycles,.since suchcurrents rapidly wear ielectrode .suriaces to conformationswhich cause itimc and amplitude jitter, thereby :requiring frequentelectrode "changes. This :invention provides a rotary spark gapgenerator which the electrodes have :a :novel :conformation whichreduces 'to :a .minimum the jitter common :to sparbrgap generators asheretofore designed and which, in :addition, provides a spark ,gap.generator in which the electrodes are so designed as to insure longlife :and uniform wear thereof.

object of this invention to provide a novel rotary :spark gap generator:for high current use in which the electrodes are .so designed as :toprovide :a minimum :of jitter of :pulse time and amplitude of the sparksgenerated thereby.

Another object of this invention :is to provide a rotary spark :gap;-generator in which the elec trodes are :oriented in a :novel :mannerwith respect to each other so as to insure long life and uniform wearthereof.

A :further bj60t10f this invention :is 130 provide 'autotary spark gapV-generator :in which the spark generated will originate from the sameelectrode each time it :is generated.

A particular object of this invention :iS to pro-- vide a rotary sparkgap .generator rinwhich the faces of the electrode are at .an angle'=with :respect to each other at the instant sparking A :more particularobject "of this invention is toprovide a rotary spark gap generatorinwhich one of the -electrodes presents a surface of small radius ofcurvature as compared to the radius'rof the opposite electrode at .theinstant sparking occurs.

Further objects and advantages of this invention, as well :as itsconstruction, arrangement', and operation, will be apparent from therl'ollowing description and claims in connection with the accompanyingdrawings, in which:

Fig. 1 is a Iront'view oi-a schematic diagram '2 of a spark gapgenerator illustrating the relative orientation of a pair of electrodesas contemplated by my invention;

Fig. 2 is a side wiew of spark gapgenerator shown in Fig. '-1 furtherillustrating "the relative orientation :of the electrodes of thegenerator;

Fig. 3 is a schematic diagram of the spark gap generator illustratingthemannerof wear of the "electrodes as-shown inFi'g. 1;

Fig.4 is a schematic :diagram of the spark gap generator illustratingthe manner of wear of the electrodes as shown in Fig. 12.

Referring to Figs. 1 and '2 there is shown a pair oi'electrodes '20 and.21 of :a spark gap genrotary electrodes'a:single'rrotary electrode anda series :of "radially mounted stationary electrodes, :or iapluralit-yof stationary electrodes and :a plurality ofradiallypmounted rotaryelectrodes. ;.A design used in existing equipment consists of a singlestationary electrode and s-ixrotary electrodes placed radially upon disc.ZLwhich in turn rotates-about ashaft '(not shown) vasjan axis.

heretofore stated, rotary spark ;.-gap e generators of common designhave proven unsatisfactory forhandling large currents .of the order ofone thousand amperes due to the high rate of wear of'the electrodes andhecauseoi the considerable jitter of pulse time and amplitude of thesparks developed :by such generators. It has been discovered that thisunsteady operation :occurs when :the spark discharge does :not originatefrom the same electrode :each time I the spark :is generated. r

In .order to control "the :spark discharge and cause it to originate.from :the same electrode each time, the stationary or positive electrode210 provided with .a-surface having :a short radius of curvature toionize the air in its vicinity, while the rotary or negative electrode'2! is provided with a surface of :longer radius of curvature in order*to-produ'ce less ionization of the :air in the vicinity of the rotaryelectrode. As shown :in Fig. -1 thisis accomplished by, in effect,pointing the and electrode 20 towards the approaching electrode 21travellingin its rotary path. As'il lustratetl in Figs. 1 and 2, rotaryelectrode '2 or a plurality of rotary electrodes "such "ibe used.

is placed on a rotary disc 22. In the plane of this disc fixed electrode20 is parallel to rotary electrode 2|, but at the instant electrodes 20and 2| are disposed sufiiciently close to each other for a sparkdischarge to occur across them, fixed electrode 20 forms an angle,preferably approximately 30 degrees, with the radial line of rotaryelectrode 2| in a plane drawn through this radius at right angles to thedisc. In other words the fixed electrode is placed parallel to therotary electrode, or electrodes, in the plane of the disc but approximately at an angle of 30 degrees with a plane perpendicular to theplane of the disc passing through the rotary electrode. As a result ofthis structure, fixed electrode 20 presents a surface of small radius ascompared to the cylindrical surface of revolving electrode 2|. As theelectrode wear progresses, an ellipse of short radii of curvature iscontinually presented, and as fixed electrode 20 becomes shorter, itmakes its spark contact lower down on the surface of each rotaryelectrode. The relative rate of deformation of the electrodes isillustrated in Figs. 3 and 4 The relative rate of wear of the fixed androtary electrodes is chosen (by electrode size, polarity, and number ofrotary electrodes) so that when the fixed electrode is completely wornaway only a small part of the total material of the rotary electrodes isconsumed. By reference to Figs. 3 and '4, it will readily be understoodthat as the electrode wear progresses, an ellipse having certain shortradii of curvature is continually presented, thereby providing fixedelectrode with a short radius of curvature in order to ionize the air inits vicinity. At the same time, rotary electrode 2| (negative electrode)suffers very little deformation and therefore presents no surfaceshaving short radii of curvature. In this manner, the spark discharge iscaused to be initiated from the same electrode each time it isgenerated, throughout the usable life of the electrodes.

While a particular arrangement of my invention has been disclosed anddescribed it is to be understood that various modifications and changesmay be made without departing from the spirit and scope thereof as setforth in the appended claims.

What is'claimed is:

1. A rotary spark gap generator comprising a rotary electrode mountedupon a rotatable disc, the longitudinal axis of said rotary electrodebeing disposed in the plane of said disc, and a stationary electrode,said stationary electrode being oriented parallel to the plane of saiddisc and at an angle to the plane perpendicular to the plane of saiddisc passing through the longitudinal axis of said rotary electrode.

2. A rotary spark gap generator comprising a plurality of rotaryelectrodes radially mounted upon a rotatable disc, the longitudinal axisof each of said rotary electrodes being disposed in the plane of saiddisc, and a stationary electrode, said stationary electrode beingoriented parallel to the plane of said disc and oriented at an angle tothe plane perpendicular to the plane of said disc passing through therotary electrode adjacent said stationary electrode at the instant aspark discharge is generated between said electrodes.

3. A rotary spark gap generator comprising a plurality of rotaryelectrodes radially mounted upon a rotatable disc, the longitudinal axisof each of said rotary electrodes being disposed in the plane of saiddisc, and a stationary electrode, said stationary electrode beingoriented parallel to the plane of said disc and oriented at an angle tothe plane perpendicular to the plane of said disc passing through thelongitudinal axis of the rotary electrode adjacent said fixed electrodeat the instant a spark discharge is generated across said electrodes,said fixed electrode having a relatively short radius of curvature ascompared to the radius of curvature of each of said rotary electrodes.

4. A rotary spark gap generator comprising a stationary electrode and anelectrode rotatable in a fixed plane, said stationary electrode beingoriented parallel to the plane of rotation of said rotary electrode,said stationary electrode also being oriented at an acute angle to saidrotary electrode at the instant a spark discharge is generated betweensaid electrodes.

5. A rotary spark gap generator comprising a rotary electrode adapted togenerate a surface of revolution upon the rotation thereof, and astationary electrode disposed in a spaced relationship to said surfaceof revolution, the distance between said stationary electrode and saidsurface of revolution being constant throughout the length of saidstationary electrode, said station ary electrode being disposed at anacute angle with respect to said rotary electrode at the instant a sparkdischarge is generated between said electrodes, said rotary electrodeand said stationary electrode making different angles with respect tothe direction of rotation of said rotary electrode at said instant ofspark discharge.

6. A rotary spark gap generator comprising a stationary electrode and arotary electrode adapted to rotate within a fixed plane of rotation, asubstantial portion of said stationary electrode being oriented parallelto said plane of rotation, the free end of said'substantial portionbeing disposed in close proximity to said rotary electrode at theinstant of a spark gap discharge, said stationary electrode beingoriented relative to said plane of rotation so thatat an instant of 'aspark gap discharge between said electrodes, said stationary electrodeintersects said rotary electrode at an acute angle, whereby the spacingbetween said electrodes at the instant of a spark gap discharge remainsconstant independent of the wear of said rotary electrode and of thesubstantial portion of said stationary electrode.

7. In a spark gap generator, a stationary electrode and an electroderotatable in a fixed plane, said stationary electrode being orientedparallel to the plane of rotation of said rotatable electrode, saidstationary electrode and said rotatable electrode making differentangles with respect to the direction of rotation of said rotatableelectrode at the instant of a spark discharge between said electrodes.

8. In a spark gap generator, an elongated stationary electrode and atleast one elongated electrode adapted to'rotate with its longitudinalaxis radial to the axis of rotation, means supporting said stationaryelectrode with its axis parallel to and displaced from the plane ofrotation of said rotatable electrode, said stationary electrode beingoriented with respect to said axis of rotation such that said rotatableelectrode is adapted to pass over the length of said stationaryelectrode once each revolution of said rotatable electrode, saidrotatable electrode when rotated in the desired direction making anacute angle with re ship with said stationary electrode.

9. In a spark gap generator, an elongated stationary cylindricalelectrode and at least one elongated cylindrical electrode adapted torotate with its longitudinal axis radial to the axis of rotation, meanssupporting said stationary electrode with its longitudinal axis parallelto the plane of rotation of said rotatable electrode, said stationaryelectrode being disposed with respect to the said axis of rotation suchthat said rotatable electrode passes over the length of said stationaryelectrode once for each revolution and makes an acute angle with saidstationary electrode which increases in magnitude as it passes over oneend of said stationary electrode to the other end of said stationaryelectrode.

10. In a spark gap generator, a movable electrode defining duringmovement thereof a predetermined surface, a stationary electrode, andmeans supporting said stationary electrode in spaced relationship tosaid surface whereby the distance between said stationary electrode andsaid surface is maintained constant during movement of said movableelectrode past said stationary electrode, said distance being of amagnitude to permit a spark discharge between said electrodes upon theapplication of a predetermined potential thereto, said stationaryelectrode further being oriented at an acute angle with respect to saidmovable electrode during movement of said movable electrode past saidstationary electrode, said electrodes defining different angles withrespect to the direction of motion of said movable electrode throughoutthe movement of said movable electrode past said stationary electrode.

11. In a spark gap generator, a movable, elongated, cylindricalelectrode, arranged to rotate in a plane and extending radially from theaxis of rotation, an elongated, stationary electrode of cylindricalshape supported with its axis parallel to the plane of rotation of saidmovable electrode and spaced from said plane of rotation an amount topermit a spark discharge between said movable and stationary electrodesas said movable electrode is rotated past said stationary electrode,said stationary electrode further being oriented at an acute angle withrespect to said movable electrode during rotation of said movalbleelectrode in the desired direction past said stationary electrode, whichangle increases in magnitude as said movable electrode passes by saidstationary electrode.

RUSSELL S. STANTON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 954,641 Marconi Apr. 12, 19101,299,823 Cockaday Apr. 8, 1919 1,170,853 Shoemaker Feb. 8, 1916 FOREIGNPATENTS Number Country Date 106,677 Germany Nov. 30, 1899 193,282Germany Nov. 29, 1907

